A scheduler for scheduling downlink transmissions of orthogonal frequency division multiple access (OFDMA) signals using spatially directed beams to a plurality of subscriber stations in a wireless network. The scheduler schedules the downlink transmissions as a function of frequency, time, and space. The scheduler further schedules downlink transmissions to a first subscriber station based on a first null space associated with at least one subscriber station previously scheduled to receive.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A base station capable of communicating with a plurality of subscriber stations in a wireless network, the base station comprising: a transceiver capable of transmitting downlink orthogonal frequency division multiple access (OFDMA) signals to the plurality of subscriber stations; an antenna array capable of transmitting the downlink OFDMA signals to the plurality of subscriber stations using spatially directed beams; and a scheduling controller capable of scheduling downlink transmissions to the plurality of subscriber stations using spatially directed transmit beams, wherein the scheduling controller schedules a first one of the plurality of subscriber stations to receive in a first time-frequency slot based on a first null space of a matrix associated with at least one subscriber station previously scheduled to receive in the first time-frequency slot.
2. The base station as set forth in claim 1 , wherein the scheduling controller is capable of determining a second one of the plurality of subscriber stations having a highest priority.
3. The base station as set forth in claim 2 , wherein the scheduling controller determines the priority of the second subscriber station using a proportional fair sharing algorithm.
4. The base station as set forth in claim 2 , wherein the second subscriber station is one of the at least one subscriber station previously scheduled to receive in the first time-frequency slot.
5. The base station as set forth in claim 2 , wherein the scheduling controller is further capable of scheduling a third one of the plurality of subscriber stations to receive in the first time-frequency slot based on a second null space associated with the first subscriber station and the at least one subscriber station previously scheduled to receive in the first time-frequency slot.
6. The base station as set forth in claim 5 , wherein the scheduling controller is further capable of comparing a received power associated with the third subscriber station to a minimum power threshold and wherein the scheduling controller, in response to a determination that the received power does not exceed the minimum power threshold, does not schedule the third subscriber station to receive in the first time-frequency slot.
7. The base station as set forth in claim 1 , wherein the scheduling controller is further capable of scheduling a second one of the plurality of subscriber stations to receive in the first time-frequency slot based on a second null space associated with the first subscriber station and the at least one subscriber station previously scheduled to receive in the first time-frequency slot.
8. The base station as set forth in claim 7 , wherein the scheduling controller is further capable of comparing a received power associated with the second subscriber station to a minimum power threshold and wherein the scheduling controller, in response to a determination that the received power does not exceed the minimum power threshold, does not schedule the second subscriber station to receive in the first time-frequency slot.
9. A wireless network comprising a plurality of base stations capable of communicating with subscriber stations, each one of the plurality of base stations comprising: a transceiver capable of transmitting downlink orthogonal frequency division multiple access (OFDMA) signals to a plurality of the subscriber stations; an antenna array capable of transmitting the downlink OFDMA signals to the plurality of subscriber stations using spatially directed beams; and a scheduling controller capable of scheduling downlink transmissions to the plurality of subscriber stations using spatially directed transmit beams, wherein the scheduling controller schedules a first one of the plurality of subscriber stations to receive in a first time-frequency slot based on a first null space of a matrix associated with at least one subscriber station previously scheduled to receive in the first time-frequency slot.
10. The wireless network as set forth in claim 9 , wherein the scheduling controller is capable of determining a second one of the plurality of subscriber stations having a highest priority.
11. The wireless network as set forth in claim 10 , wherein the scheduling controller determines the priority of the second subscriber station using a proportional fair sharing algorithm.
12. The wireless network as set forth in claim 10 , wherein the second subscriber station is one of the at least one subscriber station previously scheduled to receive in the first time-frequency slot.
13. The wireless network as set forth in claim 10 , wherein the scheduling controller is further capable of scheduling a third one of the plurality of subscriber stations to receive in the first time-frequency slot based on a second null space associated with the first subscriber station and the at least one subscriber station previously scheduled to receive in the first time-frequency slot.
14. The wireless network as set forth in claim 13 , wherein the scheduling controller is further capable of comparing a received power associated with the third subscriber station to a minimum power threshold and wherein the scheduling controller, in response to a determination that the received power does not exceed the minimum power threshold, does not schedule the third subscriber station to receive in the first time-frequency slot.
15. A method of communicating with a plurality of subscriber stations in a wireless network, the method comprising: transmitting downlink orthogonal frequency division multiple access (OFDMA) signals to at least one subscriber station in a first time-frequency slot using spatially directed beams; determining a first null space of a matrix associated with the at least one subscriber station; and scheduling a first subscriber station to receive in the first time-frequency slot based on the first null space.
16. The method as set forth in claim 15 , further comprising determining a second one of the plurality of subscriber stations having a highest priority.
17. The method as set forth in claim 16 , wherein determining the priority of the second subscriber station comprises using a proportional fair sharing algorithm.
18. The method as set forth in claim 16 , wherein the second subscriber station is one of the at least one subscriber station previously scheduled to receive in the first time-frequency slot.
19. The method as set forth in claim 16 , further comprising: determining a second null space associated with the first subscriber station and the at least one subscriber station; and scheduling a third one of the plurality of subscriber stations to receive in the first time-frequency slot based on the second null space.
20. The method as set forth in claim 19 , further comprising: comparing a received power associated with the third subscriber station to a minimum power threshold; in response to a determination that the received power does not exceed the minimum power threshold, refraining from scheduling the third subscriber station to receive in the first time-frequency slot.
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November 4, 2005
January 17, 2012
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